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# Week two a d conversion

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### Week two a d conversion

1. 1. Hi, Guillermo Delgado From México City here again. I am coming now with this new guide about how this Analog to Digital process occurs when we works over our interfaces and DAW´s. Again sorry for not to present a video but my english spoken is not as good and i want to avoid misunderstand with bad pronunciations, so here is my second week homework and as ever, hope to be useful for everyone. THANKS FRO READ!
2. 2. It could be not too easy to understand this process of how audio signals come into an interface and how a computer can translate that signal to let a DAW read correctly all that information, but here i will try to teach you in a simple way how this process happens.
3. 3. First we will define what Digital Audio means, we can define this process as the codification of an analog audio signal into binary information to let our computers and DAW´s read signals then reconvert again to analog sounds for our ears to listen the original signal again. This process is a chain of internal process which is divided principally into three important steps: “Sampling” “Quantization” and “Digital Coding”.
4. 4. To understand how a computer represents sound, consider how a film represents motion. A movie is made by taking still photos in rapid sequence at a constant rate, usually at twenty-four frames per second. When the photos are displayed in sequence at that same rate, it fools us into thinking we are seeing continuous motion, even though we are actually seeing twenty-four discrete images per second. Digital recording of sound works on the same principle. We take many discrete samples of the sound wave’s instantaneous amplitude, store that information, and later reproduce those amplitudes at the same rate to create the illusion of a continuous wave.
5. 5. The samples contain information telling your computer how the recorded signal sounded at certain instants in time. The more samples used to represent the sound the better the quality of the recorded sound. Sampling Rate is the number of times per second that the measurements (or sample) are taken. Typical rates between 15,000-52,000 samples per second.CD Sample Rate is 44.1 KHz. For every second of sound you hear, 44,100 numbers are stored (or, 88,200 for stereo).44.1 KHz is standard for synths and sampler keyboards. 48 KHz is now becoming the more common standard. Sampling s based on Nyquist law.
6. 6. Each sample of an audio signal must be described as numerical value to be stored in the computer. The numerical value expresses the instantaneous amplitude of the signal at the moment it was sampled. The range of the numbers must be sufficiently large in order to express adequately the entire amplitude range of the sound being sampled. Quantization error is unavoidable, but it can be reduced to an acceptable level by using more bits to represent each number. If we use two bytes (16 bits) per sample, the quantization error will be only 1/65,356 of the maximum signal amplitude. Since the quantization error for each sample is usually random (sometimes a little too high, sometimes a little too low), we generally hear the effect of quantization error as white noise. This noise is not present in the original signal; it is added into the digital signal by the imprecise nature of quantization. This is called quantization noise.
7. 7. Samples are grouping in packets depending on numbers of bits. More numbers of bits  Highest number of diferent packages
8. 8. Digital Coding is the last one of the processes that place takes during Conversion A/D consists of the translation of the analogical values of tension electrical that already have been quantified (average) to binary System, by means of pre-established codes . analogical Signal is going to be transformed into digital Train of impulses (succession of zero and ones).Parameters of Digital coding includes: Number of ChannelsSampling RateResolution (number of bits)Output Channels. 001 011 100 110 110 101 111 110 101 111 110 100 001011100110110101100111110101111110
9. 9. That´s all for now, any comment or doubt please make it in my post in forum. Until next week, have a great day. 001 011 100 110 110 101 111 110 101 111 110 100